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Health Check

Magnesium – Mineral for muscles, nerves and energy

Magnesium is a blood test that measures the mineral magnesium, important for muscles, nerves, heart rhythm and energy metabolism. It is often taken for muscle cramps, palpitations, fatigue or gastrointestinal issues, and is included in several health checks as part of the broader mineral status.

What is Magnesium?

Magnesium is a mineral found in bone, muscle and the body's cells. Only a small part of the body's total magnesium is found in the blood, which means a blood test does not always reflect total stores as well as it does for some other minerals.

Why is Magnesium measured in a health check?

Magnesium is needed for hundreds of chemical reactions in the body, including energy metabolism, muscle function and regulation of the heart's conduction system. The test is taken for symptoms such as muscle cramps, tingling, palpitations or in cases of gastrointestinal disease, severe vomiting or diarrhoea, and during certain drug treatments that can affect the magnesium level.

High and low values

High value: High values are uncommon in otherwise healthy people and are seen mainly with impaired kidney function or with high doses of magnesium supplements or magnesium-containing medicines such as certain laxatives and antacids.

Low value: Low values can cause muscle cramps, twitching, fatigue, palpitations and, in pronounced cases, an effect on heart rhythm. Causes include gastrointestinal disease, prolonged vomiting or diarrhoea, high alcohol consumption and certain medicines.

Reference ranges differ between laboratories, sexes and ages and are stated in your result. The information here does not replace medical assessment.

How is magnesium measured in a health check?

Magnesium is analysed in a standard venous blood sample, taken alongside the rest of the health check. The test requires no fasting, but if the health check also includes blood lipids or fasting glucose, fasting applies to the whole sample, and it's then simplest to book a morning appointment.

Since only a small part of the body's magnesium is found in the blood, a normal blood test can occur even when muscles and cells are deficient. With clear symptoms despite a normal blood value, a doctor may in some cases supplement with other ways of assessing magnesium status.

Why is magnesium measured in a blood test?

Magnesium takes part in hundreds of chemical processes in the body, including energy metabolism, protein formation, muscle contraction and nerve signalling. The mineral is also important for the heart's conduction system to function normally, meaning abnormal levels can affect heart rhythm.

A magnesium blood test is often taken for symptoms such as muscle cramps, twitching, tingling, palpitations or unexplained fatigue. It is also relevant in gastrointestinal disease, prolonged vomiting or diarrhoea, since magnesium can then be lost in abnormally large amounts through the gut.

Who should check their magnesium?

Most healthy people with a varied diet rarely have magnesium deficiency, but certain groups are at higher risk and benefit more from checking the level as part of a health check.

  • People with chronic gastrointestinal disease, such as inflammatory bowel disease or coeliac disease
  • People with high alcohol consumption
  • People with prolonged vomiting or diarrhoea
  • People treated with certain diuretics or acid-inhibiting medicines
  • People with known impaired kidney function, where high values can also occur
  • Endurance athletes with significant fluid and salt losses through sweating

How is magnesium interpreted together with other tests?

A single magnesium value is rarely interpreted entirely on its own. In a broad health check it's often seen together with potassium, calcium and kidney function, since disturbances in these minerals and electrolytes are often linked and can reinforce each other's effects on, for example, heart rhythm.

In pronounced low magnesium, a doctor may also need to review the medication list and stomach or bowel function, since the cause is often found there rather than in the blood value itself. With normal values and no symptoms, a check as part of a regular health check is usually enough without closer follow-up.

Frequently asked questions about Magnesium

What does low magnesium mean?

Low magnesium means the mineral in the blood is below the expected level, which can cause muscle cramps, twitching, fatigue and palpitations. The cause is often investigated further since several different conditions can lie behind it.

What can cause high magnesium?

High magnesium is usually due to impaired kidney function or high doses of magnesium supplements and magnesium-containing medicines, such as certain laxatives or antacids.

Do I need to fast before a magnesium test?

No, magnesium is not significantly affected by food. If the test is included in a health check with fasting glucose or blood lipids, fasting still applies to those tests.

Which health checks include magnesium?

Magnesium is included in several of Labkollen's broad health checks, often together with other minerals and electrolytes. All tests that include the marker are listed further down this page.

Can you have magnesium deficiency despite a normal blood test?

Yes. Since only a small part of the body's magnesium is found in the blood, cells can be deficient even though the blood test looks normal. With persistent symptoms, the assessment is made together with the clinical picture.

Can diet and supplements affect the magnesium level?

Yes. Magnesium is found in, among other things, leafy green vegetables, nuts, wholegrains and legumes. Supplements raise the level, but high doses can in rare cases give too high values, especially with impaired kidney function.

Is magnesium included in a standard health check with a blood test?

Magnesium is included in several of Labkollen's broad health checks, often as part of mineral and electrolyte status. Which tests include the marker are listed further down the page.

Health checks that include Magnesium

Magnesium is included in 11 of Labkollen's health checks. Analysis name in the result: Magnesium.

  • Man +

    49 markers

    Labkollens mest omfattande kontroll för män – inklusive testosteron, PSA och hjärt-kärlmarkörer.

    2 095 krMed prenumeration (årlig hälsokontroll): 1 676 kr

    See the test

  • Kvinna +

    44 markers

    Labkollens mest omfattande kontroll för kvinnor – inklusive järnstatus, sköldkörtel och hormoner.

    2 095 krMed prenumeration (årlig hälsokontroll): 1 676 kr

    See the test

  • Standard

    37 markers

    Bred hälsokontroll över blodsocker, blodfetter, blodvärde, lever, njurar, sköldkörtel och vitaminer.

    1 795 krMed prenumeration (årlig hälsokontroll): 1 436 kr

    See the test

  • Seniorkollen

    32 markers

    Anpassad kontroll för dig över 65 med fokus på hjärta, njurar, sköldkörtel och näringsstatus.

    1 299 krMed prenumeration (årlig hälsokontroll): 1 039 kr

    See the test

  • Gravid

    26 markers

    Kontroll under graviditet – blodvärde, järn, sköldkörtel, vitaminer och hCG.

    1 099 krMed prenumeration (årlig hälsokontroll): 879 kr

    See the test

  • Vitamin- och mineralkollen

    18 markers

    D-vitamin, B12, folat, järn och mineraler för dig som vill kolla näringsstatus.

    1 099 krMed prenumeration (årlig hälsokontroll): 879 kr

    See the test

  • Uthållighetssport

    16 markers

    För löpare, cyklister och simmare – järnstatus, energiomsättning och återhämtning.

    1 499 krMed prenumeration (årlig hälsokontroll): 1 199 kr

    See the test

  • Lagsport

    16 markers

    För lagidrottare – energi, järn, återhämtning och stresshormon.

    1 499 krMed prenumeration (årlig hälsokontroll): 1 199 kr

    See the test

  • Styrkesport

    15 markers

    För styrketräning – hormoner, muskelmarkörer, lever och mineraler.

    1 499 krMed prenumeration (årlig hälsokontroll): 1 199 kr

    See the test

  • Kampsport

    15 markers

    För kampsportare – återhämtning, hormoner, inflammation och järn.

    1 499 krMed prenumeration (årlig hälsokontroll): 1 199 kr

    See the test

  • Gymnastik och konståkning

    14 markers

    För teknikidrotter – benhälsa, järnstatus, sköldkörtel och tillväxtmarkörer.

    1 499 krMed prenumeration (årlig hälsokontroll): 1 199 kr

    See the test

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